.

go/internal/xtracing/tracetest/example_test.go

@@ -26,6 +26,8 @@ package tracetest_test
 
 import (
 	"fmt"
+	"os"
+	"os/exec"
 	"strings"
 	"sync"
 	"testing"
@@ -87,19 +89,41 @@ func routeEvent(event interface{}) (stream string) {
 	return strings.ToLower(who[:i])
 }
 
-// verify calls tracetest.Verify on f with first preparing tracing setup and event delivery.
-// It also verifies that tracetest catches errors as expected. // TODO
-func verify(t *testing.T, f func(t *tracetest.T)) {
-	tracetest.Verify(t, func(t *tracetest.T) {
-		// setup tracing to deliver trace events to t.
-		pg := setupTracing(t)
-		t.Cleanup(pg.Done)
-		// tell t to which stream an event should go.
-		t.SetEventRouter(routeEvent)
-
-		// run test code
-		f(t)
-	})
+// verify calls tracetest.Verify on f with first preparing tracing setup and events delivery.
+// It also verifies that tracetest detects errors as expected.
+func verify(t *testing.T, f func(t *tracetest.T), targvExtra ...string) {
+	if os.Getenv("TRACETEST_EX_VERIFY_IN_SUBPROCESS") == "1" {
+		tracetest.Verify(t, func(t *tracetest.T) {
+			// setup tracing to deliver trace events to t.
+			pg := setupTracing(t)
+			t.Cleanup(pg.Done)
+			// tell t to which stream an event should go.
+			t.SetEventRouter(routeEvent)
+
+			// run test code
+			f(t)
+		})
+		return
+	}
+
+	// spawn the test in subprocess and verify its output
+	outOK, ok := testExpect[t.Name()]
+	if !ok {
+		panic(fmt.Sprintf("testExpect[%q] not defined", t.Name()))
+	}
+	argv := []string{"-test.run="+t.Name()}
+	argv = append(argv, targvExtra...)
+	cmd := exec.Command(os.Args[0], argv...)
+	cmd.Env = append(os.Environ(), "TRACETEST_EX_VERIFY_IN_SUBPROCESS=1")
+	bout, err := cmd.CombinedOutput()
+	out := string(bout)
+	if err != nil {
+		t.Log(out)
+		t.Fatal(err) // XXX check first it is not "exit code"
+	}
+
+	// XXX verify out
+	_ = outOK
 }
 
 
@@ -158,5 +182,32 @@ func TestDeadlock(t *testing.T) {
 		// the checker expects something on stream "t3", but there is
 		// no event sent there -> deadlock.
 		t.Expect("t3", eventHi("zzz"))
-	})
+	}, "-tracetest.deadtime=0.5s")
+}
+
+// XXX race bug with sleep caught only by delay injection
+
+
+// --------
+
+// testExpect maps <test name> -> expected output
+var testExpect = map[string]string{
+	"Test2ThreadsOK": "",
+	"TestDeadlock": `
+--- FAIL: TestDeadlock (.+s)
+    example_test.go:179: t3: recv: deadlock waiting for *tracetest_test.eventHi
+    example_test.go:179: test shutdown: #streams: 3,  #(pending events): 2
+        t1      <- tracetest_test.eventHi T1·A
+        t2      <- tracetest_test.eventHi T2·B
+        # t3
+
+    tracetest.go:175: t2: send: canceled (test failed)
+    .*
+
+    tracetest.go:175: t1: send: canceled (test failed)
+    .*
+
+FAIL
+exit status 1
+`,
 }